A woman who lured a pregnant teen to her apartment, drugged her, cut the child from the womb to try to pass it off as her own and killed the teen was sentenced Monday to life in prison plus 20 years.

The penalty for Andrea Curry-Demus, 40, was largely determined in March when Allegheny County Judge Jeffrey Manning found her guilty but mentally ill of second-degree murder.

That carries the mandatory life sentence imposed formally on Monday, and Manning tacked on 20 years for kidnapping, saying, "It would be a huge injustice if you were ever released into society."

At her sentencing, Curry-Demus briefly turned around and faced the family of her victim, Kia Johnson, 18.

"I want to apologize to the family," Curry-Demus said, before facing the judge and saying, "I'm sorry."

Johnson's mother, Darlene Lee, said she was satisfied with the life sentence.

"I don't want her to have the death penalty. I want her to suffer, I really do," Lee said. "I want her to suffer and think about what she did to my daughter and see my daughter's face every day that she wakes up."

Curry-Demus met Johnson at the Allegheny County Jail in July 2008 while both were visiting inmates, prosecutors said. Curry-Demus had been telling her family she was pregnant, even putting her name on another woman's ultrasound that she showed people and decorating a nursery.

Curry-Demus eventually befriended Johnson by offering her clothes for her unborn son and a ride home from the jail on July 15, 2008. But Curry-Demus got Johnson to her own Wilkinsburg apartment, drugged her, bound her with duct tape and cut the baby from her.

Curry-Demus wrapped Johnson's body in more tape, plastic wrap and bags and a comforter before stuffing it in a space behind the bed. Johnson died of a combination of blood loss and suffocation, prosecutors said.

Curry-Demus then told her sister that she gave birth, but hospital tests showed she wasn't the mother. Curry-Demus then told police she bought the baby from a crack addict, but police found Johnson's body after Curry-Demus' neighbors reported the stench of decomposition.

Curry-Demus had been sentenced to three to 10 years in prison in a similar plot two decades ago. In May 1990, she stabbed a woman in an apparent plot to steal her newborn and the next day kidnapped another baby from a hospital. She pleaded guilty in January 1991 to kidnapping, aggravated assault, concealing the whereabouts of a child and related offenses.